Trifolium repens L.
Family - Fabaceae
Stems - Herbaceous, typically glabrous, creeping, rooting at nodes.
Leaves - Alternate, trifoliolate, petiolate. Petioles to +15cm long, glabrous, with a shallow adaxial groove. Stipules sheathing, scarious, free portion 5-6mm long. Leaflets 3, broadly ovate to orbicular with striate nerves (veins), denticulate in basal 1/2 on margins, glabrous, to 2cm in diameter, with inverted "V"-shaped splotch adaxially, shiny green abaxially, dull green adaxially. Petiolules very short, pilose, to 1mm long.
Inflorescence - Terminal globose cluster of +/-60 flowers. Peduncle to +/-20cm tall, carinate, glabrous or with a few sparse hairs. Pedicels +/-4mm long, glabrous or with a few spare hairs. Each pedicel subtended by a single small scarious bract. Bracts 1-2mm long, .5mm broad, sometimes with a green midvein. Pedicels erect in flower, recurved in fruit.
Flowers - Corolla whitish, fading to pink or tan, papilionaceous, glabrous. Standard 8-9mm long, 4mm broad. Keels apically fused. Wings adnate to keels near the apex. Wings and keels fused to stamen tube. Stamens diadelphous, glabrous. Anthers yellow, .2-.3mm long. Ovary green, glabrous, 2.1mm long in flower. Style glabrous, 3mm long, upcurved, translucent. Stigma capitate. Calyx weakly bilabiate. The upper lip 2-lobed. Lobes attenuate, 2mm long. Lower lip 3-lobed. Lobes to 1.4mm long, attenuate. Calyx tube 2.5mm long, 1.5mm in diameter, glabrous internally and externally, pale green with darker green areas. Tube sometimes reddish at the base of the lobes. Fruit to 5mm long, linear, terete, 3-4 seeded.
Flowering - May - November.
Habitat - Waste ground, pastures, open fields, roadsides, railroads.
Origin - Native to Eurasia.
Other info. - One of the
most common "weeds" in Missouri, this plant can form large mats up to 2m
in diameter. It is not uncommon to find entire fields covered with this
species and other introduced species such as Coronilla varia
and T. pratense.
Photographs taken in the Ozark Scenic Riverways, Shannon County, MO., 6-16-05, and in Auburn, AL., 4-17-05.